Re: [PATCH v3 2/4] rtc: mediatek: add driver for RTC on MT7622 SoC

From: Yingjoe Chen
Date: Tue Oct 24 2017 - 12:38:27 EST



Sean,

Looks good to me. You can add if you want:

Reviewed-by: Yingjoe Chen <yingjoe.chen@xxxxxxxxxxxx>

Joe.C


On Mon, 2017-10-23 at 15:16 +0800, sean.wang@xxxxxxxxxxxx wrote:
> From: Sean Wang <sean.wang@xxxxxxxxxxxx>
>
> This patch introduces the driver for the RTC on MT7622 SoC.
>
> Signed-off-by: Sean Wang <sean.wang@xxxxxxxxxxxx>
> ---
> drivers/rtc/Kconfig | 10 ++
> drivers/rtc/Makefile | 1 +
> drivers/rtc/rtc-mt7622.c | 422 +++++++++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 433 insertions(+)
> create mode 100644 drivers/rtc/rtc-mt7622.c
>
> diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
> index e0e58f3..fd9b590 100644
> --- a/drivers/rtc/Kconfig
> +++ b/drivers/rtc/Kconfig
> @@ -1705,6 +1705,16 @@ config RTC_DRV_MOXART
> This driver can also be built as a module. If so, the module
> will be called rtc-moxart
>
> +config RTC_DRV_MT7622
> + tristate "MediaTek SoC based RTC"
> + depends on ARCH_MEDIATEK || COMPILE_TEST
> + help
> + This enables support for the real time clock built in the MediaTek
> + SoCs.
> +
> + This drive can also be built as a module. If so, the module
> + will be called rtc-mt7622.
> +
> config RTC_DRV_MT6397
> tristate "Mediatek Real Time Clock driver"
> depends on MFD_MT6397 || (COMPILE_TEST && IRQ_DOMAIN)
> diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
> index 7230014..eb47f8c 100644
> --- a/drivers/rtc/Makefile
> +++ b/drivers/rtc/Makefile
> @@ -101,6 +101,7 @@ obj-$(CONFIG_RTC_DRV_MOXART) += rtc-moxart.o
> obj-$(CONFIG_RTC_DRV_MPC5121) += rtc-mpc5121.o
> obj-$(CONFIG_RTC_DRV_VRTC) += rtc-mrst.o
> obj-$(CONFIG_RTC_DRV_MSM6242) += rtc-msm6242.o
> +obj-$(CONFIG_RTC_DRV_MT7622) += rtc-mt7622.o
> obj-$(CONFIG_RTC_DRV_MT6397) += rtc-mt6397.o
> obj-$(CONFIG_RTC_DRV_MV) += rtc-mv.o
> obj-$(CONFIG_RTC_DRV_MXC) += rtc-mxc.o
> diff --git a/drivers/rtc/rtc-mt7622.c b/drivers/rtc/rtc-mt7622.c
> new file mode 100644
> index 0000000..d79b9ae
> --- /dev/null
> +++ b/drivers/rtc/rtc-mt7622.c
> @@ -0,0 +1,422 @@
> +/*
> + * Driver for MediaTek SoC based RTC
> + *
> + * Copyright (C) 2017 Sean Wang <sean.wang@xxxxxxxxxxxx>
> + *
> + * This program is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU General Public License as
> + * published by the Free Software Foundation; either version 2 of
> + * the License, or (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> + * GNU General Public License for more details.
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/interrupt.h>
> +#include <linux/module.h>
> +#include <linux/of_address.h>
> +#include <linux/of_device.h>
> +#include <linux/platform_device.h>
> +#include <linux/rtc.h>
> +
> +#define MTK_RTC_DEV KBUILD_MODNAME
> +
> +#define MTK_RTC_PWRCHK1 0x4
> +#define RTC_PWRCHK1_MAGIC 0xc6
> +
> +#define MTK_RTC_PWRCHK2 0x8
> +#define RTC_PWRCHK2_MAGIC 0x9a
> +
> +#define MTK_RTC_KEY 0xc
> +#define RTC_KEY_MAGIC 0x59
> +
> +#define MTK_RTC_PROT1 0x10
> +#define RTC_PROT1_MAGIC 0xa3
> +
> +#define MTK_RTC_PROT2 0x14
> +#define RTC_PROT2_MAGIC 0x57
> +
> +#define MTK_RTC_PROT3 0x18
> +#define RTC_PROT3_MAGIC 0x67
> +
> +#define MTK_RTC_PROT4 0x1c
> +#define RTC_PROT4_MAGIC 0xd2
> +
> +#define MTK_RTC_CTL 0x20
> +#define RTC_RC_STOP BIT(0)
> +
> +#define MTK_RTC_DEBNCE 0x2c
> +#define RTC_DEBNCE_MASK GENMASK(2, 0)
> +
> +#define MTK_RTC_INT 0x30
> +#define RTC_INT_AL_STA BIT(4)
> +
> +/*
> + * Ranges from 0x40 to 0x78 provide RTC time setup for year, month,
> + * day of month, day of week, hour, minute and second.
> + */
> +#define MTK_RTC_TREG(_t, _f) (0x40 + (0x4 * (_f)) + ((_t) * 0x20))
> +
> +#define MTK_RTC_AL_CTL 0x7c
> +#define RTC_AL_EN BIT(0)
> +#define RTC_AL_ALL GENMASK(7, 0)
> +
> +/*
> + * The offset is used in the translation for the year between in struct
> + * rtc_time and in hardware register MTK_RTC_TREG(x,MTK_YEA)
> + */
> +#define MTK_RTC_TM_YR_OFFSET 100
> +
> +/*
> + * The lowest value for the valid tm_year. RTC hardware would take incorrectly
> + * tm_year 100 as not a leap year and thus it is also required being excluded
> + * from the valid options.
> + */
> +#define MTK_RTC_TM_YR_L (MTK_RTC_TM_YR_OFFSET + 1)
> +
> +/*
> + * The most year the RTC can hold is 99 and the next to 99 in year register
> + * would be wraparound to 0, for MT7622.
> + */
> +#define MTK_RTC_HW_YR_LIMIT 99
> +
> +/* The highest value for the valid tm_year */
> +#define MTK_RTC_TM_YR_H (MTK_RTC_TM_YR_OFFSET + MTK_RTC_HW_YR_LIMIT)
> +
> +/* Simple macro helps to check whether the hardware supports the tm_year */
> +#define MTK_RTC_TM_YR_VALID(_y) ((_y) >= MTK_RTC_TM_YR_L && \
> + (_y) <= MTK_RTC_TM_YR_H)
> +
> +/* Types of the function the RTC provides are time counter and alarm. */
> +enum {
> + MTK_TC,
> + MTK_AL,
> +};
> +
> +/* Indexes are used for the pointer to relevant registers in MTK_RTC_TREG */
> +enum {
> + MTK_YEA,
> + MTK_MON,
> + MTK_DOM,
> + MTK_DOW,
> + MTK_HOU,
> + MTK_MIN,
> + MTK_SEC
> +};
> +
> +struct mtk_rtc {
> + struct rtc_device *rtc;
> + void __iomem *base;
> + int irq;
> + struct clk *clk;
> +};
> +
> +static void mtk_w32(struct mtk_rtc *rtc, u32 reg, u32 val)
> +{
> + writel_relaxed(val, rtc->base + reg);
> +}
> +
> +static u32 mtk_r32(struct mtk_rtc *rtc, u32 reg)
> +{
> + return readl_relaxed(rtc->base + reg);
> +}
> +
> +static void mtk_rmw(struct mtk_rtc *rtc, u32 reg, u32 mask, u32 set)
> +{
> + u32 val;
> +
> + val = mtk_r32(rtc, reg);
> + val &= ~mask;
> + val |= set;
> + mtk_w32(rtc, reg, val);
> +}
> +
> +static void mtk_set(struct mtk_rtc *rtc, u32 reg, u32 val)
> +{
> + mtk_rmw(rtc, reg, 0, val);
> +}
> +
> +static void mtk_clr(struct mtk_rtc *rtc, u32 reg, u32 val)
> +{
> + mtk_rmw(rtc, reg, val, 0);
> +}
> +
> +static void mtk_rtc_hw_init(struct mtk_rtc *hw)
> +{
> + /* The setup of the init sequence is for allowing RTC got to work */
> + mtk_w32(hw, MTK_RTC_PWRCHK1, RTC_PWRCHK1_MAGIC);
> + mtk_w32(hw, MTK_RTC_PWRCHK2, RTC_PWRCHK2_MAGIC);
> + mtk_w32(hw, MTK_RTC_KEY, RTC_KEY_MAGIC);
> + mtk_w32(hw, MTK_RTC_PROT1, RTC_PROT1_MAGIC);
> + mtk_w32(hw, MTK_RTC_PROT2, RTC_PROT2_MAGIC);
> + mtk_w32(hw, MTK_RTC_PROT3, RTC_PROT3_MAGIC);
> + mtk_w32(hw, MTK_RTC_PROT4, RTC_PROT4_MAGIC);
> + mtk_rmw(hw, MTK_RTC_DEBNCE, RTC_DEBNCE_MASK, 0);
> + mtk_clr(hw, MTK_RTC_CTL, RTC_RC_STOP);
> +}
> +
> +static void mtk_rtc_get_alarm_or_time(struct mtk_rtc *hw, struct rtc_time *tm,
> + int time_alarm)
> +{
> + u32 year, mon, mday, wday, hour, min, sec;
> +
> + /*
> + * Read again until the field of the second is not changed which
> + * ensures all fields in the consistent state. Note that MTK_SEC must
> + * be read first. In this way, it guarantees the others remain not
> + * changed when the results for two MTK_SEC consecutive reads are same.
> + */
> + do {
> + sec = mtk_r32(hw, MTK_RTC_TREG(time_alarm, MTK_SEC));
> + min = mtk_r32(hw, MTK_RTC_TREG(time_alarm, MTK_MIN));
> + hour = mtk_r32(hw, MTK_RTC_TREG(time_alarm, MTK_HOU));
> + wday = mtk_r32(hw, MTK_RTC_TREG(time_alarm, MTK_DOW));
> + mday = mtk_r32(hw, MTK_RTC_TREG(time_alarm, MTK_DOM));
> + mon = mtk_r32(hw, MTK_RTC_TREG(time_alarm, MTK_MON));
> + year = mtk_r32(hw, MTK_RTC_TREG(time_alarm, MTK_YEA));
> + } while (sec != mtk_r32(hw, MTK_RTC_TREG(time_alarm, MTK_SEC)));
> +
> + tm->tm_sec = sec;
> + tm->tm_min = min;
> + tm->tm_hour = hour;
> + tm->tm_wday = wday;
> + tm->tm_mday = mday;
> + tm->tm_mon = mon - 1;
> +
> + /* Rebase to the absolute year which userspace queries */
> + tm->tm_year = year + MTK_RTC_TM_YR_OFFSET;
> +}
> +
> +static void mtk_rtc_set_alarm_or_time(struct mtk_rtc *hw, struct rtc_time *tm,
> + int time_alarm)
> +{
> + u32 year;
> +
> + /* Rebase to the relative year which RTC hardware requires */
> + year = tm->tm_year - MTK_RTC_TM_YR_OFFSET;
> +
> + mtk_w32(hw, MTK_RTC_TREG(time_alarm, MTK_YEA), year);
> + mtk_w32(hw, MTK_RTC_TREG(time_alarm, MTK_MON), tm->tm_mon + 1);
> + mtk_w32(hw, MTK_RTC_TREG(time_alarm, MTK_DOW), tm->tm_wday);
> + mtk_w32(hw, MTK_RTC_TREG(time_alarm, MTK_DOM), tm->tm_mday);
> + mtk_w32(hw, MTK_RTC_TREG(time_alarm, MTK_HOU), tm->tm_hour);
> + mtk_w32(hw, MTK_RTC_TREG(time_alarm, MTK_MIN), tm->tm_min);
> + mtk_w32(hw, MTK_RTC_TREG(time_alarm, MTK_SEC), tm->tm_sec);
> +}
> +
> +static irqreturn_t mtk_rtc_alarmirq(int irq, void *id)
> +{
> + struct mtk_rtc *hw = (struct mtk_rtc *)id;
> + u32 irq_sta;
> +
> + irq_sta = mtk_r32(hw, MTK_RTC_INT);
> + if (irq_sta & RTC_INT_AL_STA) {
> + /* Stop alarm also implicitly disables the alarm interrupt */
> + mtk_w32(hw, MTK_RTC_AL_CTL, 0);
> + rtc_update_irq(hw->rtc, 1, RTC_IRQF | RTC_AF);
> +
> + /* Ack alarm interrupt status */
> + mtk_w32(hw, MTK_RTC_INT, RTC_INT_AL_STA);
> + return IRQ_HANDLED;
> + }
> +
> + return IRQ_NONE;
> +}
> +
> +static int mtk_rtc_gettime(struct device *dev, struct rtc_time *tm)
> +{
> + struct mtk_rtc *hw = dev_get_drvdata(dev);
> +
> + mtk_rtc_get_alarm_or_time(hw, tm, MTK_TC);
> +
> + return rtc_valid_tm(tm);
> +}
> +
> +static int mtk_rtc_settime(struct device *dev, struct rtc_time *tm)
> +{
> + struct mtk_rtc *hw = dev_get_drvdata(dev);
> +
> + if (!MTK_RTC_TM_YR_VALID(tm->tm_year))
> + return -EINVAL;
> +
> + /* Stop time counter before setting a new one*/
> + mtk_set(hw, MTK_RTC_CTL, RTC_RC_STOP);
> +
> + mtk_rtc_set_alarm_or_time(hw, tm, MTK_TC);
> +
> + /* Restart the time counter */
> + mtk_clr(hw, MTK_RTC_CTL, RTC_RC_STOP);
> +
> + return 0;
> +}
> +
> +static int mtk_rtc_getalarm(struct device *dev, struct rtc_wkalrm *wkalrm)
> +{
> + struct mtk_rtc *hw = dev_get_drvdata(dev);
> + struct rtc_time *alrm_tm = &wkalrm->time;
> +
> + mtk_rtc_get_alarm_or_time(hw, alrm_tm, MTK_AL);
> +
> + wkalrm->enabled = !!(mtk_r32(hw, MTK_RTC_AL_CTL) & RTC_AL_EN);
> + wkalrm->pending = !!(mtk_r32(hw, MTK_RTC_INT) & RTC_INT_AL_STA);
> +
> + return 0;
> +}
> +
> +static int mtk_rtc_setalarm(struct device *dev, struct rtc_wkalrm *wkalrm)
> +{
> + struct mtk_rtc *hw = dev_get_drvdata(dev);
> + struct rtc_time *alrm_tm = &wkalrm->time;
> +
> + if (!MTK_RTC_TM_YR_VALID(alrm_tm->tm_year))
> + return -EINVAL;
> +
> + /*
> + * Stop the alarm also implicitly including disables interrupt before
> + * setting a new one.
> + */
> + mtk_clr(hw, MTK_RTC_AL_CTL, RTC_AL_EN);
> +
> + /*
> + * Avoid contention between mtk_rtc_setalarm and IRQ handler so that
> + * disabling the interrupt and awaiting for pending IRQ handler to
> + * complete.
> + */
> + synchronize_irq(hw->irq);
> +
> + mtk_rtc_set_alarm_or_time(hw, alrm_tm, MTK_AL);
> +
> + /* Restart the alarm with the new setup */
> + mtk_w32(hw, MTK_RTC_AL_CTL, RTC_AL_ALL);
> +
> + return 0;
> +}
> +
> +static const struct rtc_class_ops mtk_rtc_ops = {
> + .read_time = mtk_rtc_gettime,
> + .set_time = mtk_rtc_settime,
> + .read_alarm = mtk_rtc_getalarm,
> + .set_alarm = mtk_rtc_setalarm,
> +};
> +
> +static const struct of_device_id mtk_rtc_match[] = {
> + { .compatible = "mediatek,mt7622-rtc" },
> + { .compatible = "mediatek,soc-rtc" },
> + {},
> +};
> +
> +static int mtk_rtc_probe(struct platform_device *pdev)
> +{
> + struct mtk_rtc *hw;
> + struct resource *res;
> + int ret;
> +
> + hw = devm_kzalloc(&pdev->dev, sizeof(*hw), GFP_KERNEL);
> + if (!hw)
> + return -ENOMEM;
> +
> + platform_set_drvdata(pdev, hw);
> +
> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + hw->base = devm_ioremap_resource(&pdev->dev, res);
> + if (IS_ERR(hw->base))
> + return PTR_ERR(hw->base);
> +
> + hw->clk = devm_clk_get(&pdev->dev, "rtc");
> + if (IS_ERR(hw->clk)) {
> + dev_err(&pdev->dev, "No clock\n");
> + return PTR_ERR(hw->clk);
> + }
> +
> + ret = clk_prepare_enable(hw->clk);
> + if (ret)
> + return ret;
> +
> + hw->irq = platform_get_irq(pdev, 0);
> + if (hw->irq < 0) {
> + dev_err(&pdev->dev, "No IRQ resource\n");
> + ret = hw->irq;
> + goto err;
> + }
> +
> + ret = devm_request_irq(&pdev->dev, hw->irq, mtk_rtc_alarmirq,
> + 0, dev_name(&pdev->dev), hw);
> + if (ret) {
> + dev_err(&pdev->dev, "Can't request IRQ\n");
> + goto err;
> + }
> +
> + mtk_rtc_hw_init(hw);
> +
> + device_init_wakeup(&pdev->dev, true);
> +
> + hw->rtc = devm_rtc_device_register(&pdev->dev, pdev->name,
> + &mtk_rtc_ops, THIS_MODULE);
> + if (IS_ERR(hw->rtc)) {
> + ret = PTR_ERR(hw->rtc);
> + dev_err(&pdev->dev, "Unable to register device\n");
> + goto err;
> + }
> +
> + return 0;
> +err:
> + clk_disable_unprepare(hw->clk);
> +
> + return ret;
> +}
> +
> +static int mtk_rtc_remove(struct platform_device *pdev)
> +{
> + struct mtk_rtc *hw = platform_get_drvdata(pdev);
> +
> + clk_disable_unprepare(hw->clk);
> +
> + return 0;
> +}
> +
> +#ifdef CONFIG_PM_SLEEP
> +static int mtk_rtc_suspend(struct device *dev)
> +{
> + struct mtk_rtc *hw = dev_get_drvdata(dev);
> +
> + if (device_may_wakeup(dev))
> + enable_irq_wake(hw->irq);
> +
> + return 0;
> +}
> +
> +static int mtk_rtc_resume(struct device *dev)
> +{
> + struct mtk_rtc *hw = dev_get_drvdata(dev);
> +
> + if (device_may_wakeup(dev))
> + disable_irq_wake(hw->irq);
> +
> + return 0;
> +}
> +
> +static SIMPLE_DEV_PM_OPS(mtk_rtc_pm_ops, mtk_rtc_suspend, mtk_rtc_resume);
> +
> +#define MTK_RTC_PM_OPS (&mtk_rtc_pm_ops)
> +#else /* CONFIG_PM */
> +#define MTK_RTC_PM_OPS NULL
> +#endif /* CONFIG_PM */
> +
> +static struct platform_driver mtk_rtc_driver = {
> + .probe = mtk_rtc_probe,
> + .remove = mtk_rtc_remove,
> + .driver = {
> + .name = MTK_RTC_DEV,
> + .of_match_table = mtk_rtc_match,
> + .pm = MTK_RTC_PM_OPS,
> + },
> +};
> +
> +module_platform_driver(mtk_rtc_driver);
> +
> +MODULE_DESCRIPTION("MediaTek SoC based RTC Driver");
> +MODULE_AUTHOR("Sean Wang <sean.wang@xxxxxxxxxxxx>");
> +MODULE_LICENSE("GPL");